Multiple-deck pulp thickener



c. w. ANKENY MULTIPLE DECK PULP THICKENER Filed April 26, 1922 March 30,1926. 1,578,625

' INVENTOR BY ULEMENI-WANKENji z Patented Mar. 30, 1926.

UNITED STATES PATENT OFFICE.

CLEMENT W, ANKENY, OF COLORADO SPRINGS, COLORADO, ASSIGNOR TO THE DORR COMPANY, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE.

MULTIPLE-DECK PULP THICKENER.

Application filed April 26, 1922. Serial N0. 556,816.

To all whom it may concern Be it known that I, CLEMENT WV. ANKENY,

a citizen of' the United States, residing at 21 North Thirteenth Street, in the city of Colorado Springs, in the county of El Paso and State of Colorado, have invented a new and useful Improvement in Multiple-Deck Pulp Thickeners, of which the following is a specification. D

My invention relates to improvements in multiple-deck pulp thickeners, .in which the pulp is received into the tank near its bot tom where the pulp is thick, the lighter fluid portion rising through a multiplicity of decks to a single outlet at the top where light watery overflow escapes and the heavy thickened pulp is caused to settle down through protecting central conduits to an outlet in the central part of the bottom of the tank by the influence of their specific gravity and slight agitation, and the objects of my different inventions are, first, to provide an automatic regulation to'be applied to the thickeners in operation and equipped with one or a multiplicity of settling surfaces; second, to eliminate the use of a multiplicity of intakes and discharges and liquid overflows and to use but one common discharge for the thickened pulp with but one liquid overflow, irrespective of the multiplicity of settling surfaces employed, thus saving cost of their installation and upkeep; third, to provide an appliance that will permit the solids and liquids to seek and move to their own specific level in a thickening unit in a tank where there is a multiplicity of the settling surfaces, and without the aid or supervision of human agencies; fourth, to simplify the appliances for thickening solids in fluid suspension; fifth, to provide a feed means that will automatically keep every compartment operating at full capacity and to provide inter-compartment discharges and feed means with but one liquid overflow; I attain these objects by means of the appliance illustrated in the accompanying drawing, in which Figure 1 is a sectional elevation of my multiple-deck pulp thickener; Fig. 2 is a plan View taken 011 line aa of the tank; 6, indicates by arrows the up-flow.

of the unsettled pulp from the lower compartment to the compartment above; 7, indicates short lengths of piping of suitable diameters through which the pulp of lighter specific gravity rises to the deck above, and these tubes 7 serve to separate occluded air which if allowed to rise with the pulp would retard thickening and classification; 8, indicates by arrows the direction and escape of the separated air; 9, indicates tubes of suitable size and length to direct the downward flow of the thickened pulp without diffusion; l010'10, indicate the three additional upper decks in this construction, but any additional reasonable number of decks may be used to save floorspace and roofing, etc.; 11, indicates the bottom deck of this particular design which is of standard construction; 12, indicates the surface rakes which are of standard construction; 13, indicates holes in the decks through which the up-feed of the pulp passes.

It has been the practice to add thickening surfaces oftrays above each other from time to time to save floor space and to save roofing, etc., and in so doing it has been the practice to add separate feed and outlet ineans as each has been considered separate- I find by practical milling that the place to supply the unclarified pulp is at the bottom of the tank as through the intake pipe 15, and that the difference in the specific gravity will immediately direct the unclarified pulp upward toward the outlet or,

overflow at 4, allowingthe solid matter to separate from the liquid in its tortuous course. The means shown for separating the gases from the fluid and compelling or allowing them to escape upward through the Openings 8, and the pipe 14, is very useful to prevent bubbles and usual agitation which interfere with the settlement of the solids that are so nearly of the specific gravity of the suspending fluids.

The difference in the specific gravity of the thickened pulp descending through the tubes from the several decks, and the unclarified pulp, is suflicient to protect it from mixing and therefore it settles like other serdimentary pulp to and through the outlet 1 7 It will be noticed that the outlet pipe 16 of the overflow has no means of regulating or shutting off the ,flow, such as a cook. The fact is that this form of supplying the pulp at the bottom or near the bottom. of one side of the tank obviates the need of a shu't-ofl' cock. This saves the time of a man. The trays are in the form of inverted hollow cones, and are not agitated, but the sweep of the rakes comes very close to the top surface of each deck, having a more rapid movement near their outer edge than near the inner edge where the heavier condensed solids are gathering at all times, as the lighter pulp is-held in suspension nearer the outer edge of the tank as it rises through the tubes 7 and the openings 13.

It is obvious that the overflow will be controlled by the supply of the feed below,

ill

' manner.

tion will flow outwardly and upwardly unwhich is controlled in the usual standard The lighter portions of the soluder the rising surface of the deck above it as it is displaced by the descending solids assin downwardly through the tubes 9.

n eacli compartment solidswill settle upon the deck below it and tend toward the lower central portions thereof.

It will be noted that the group of decks or trays is fed in series, that the action is in series and that the clearness of the overflow will depend upon the number of the series in a great measure.

I claim- 1 A settling apparatus comprising a plurality of. superposed settling compartments having central openings for the downward discharge of settled solids, and. having openings connecting adjacent compartments for the'upflow of supernatant liquid, and

scraping means passing over the bottom of each compartment and immediately adjacent thereto to impel settled solids toward the solids discharge opening, said scraping means assing' over the openings for upward flow o supernatant liquid. 1

2. Settling apparatus comprising a plurality of superposed settling compartments having central openingsthrough their bottom walls for the downward discharge of settled solids and a plurality oftvertically aligned openings in said walls distributed around the periphery of the compartments for upward flow of supernatant liquid, the latter openings in adjacent bottom walls being aligned to provide unobstructed vertical passages for said liquid, and means for mechanically impelling settled solids to the solids discharge openings.

3. Settling apparatus including a tank having a plurality of trays, a rotatable shaft extending upwardly through said trays with radially extending arms secured thereto and movably positioned above each of said trays, rakes extending downwardly from said arms adapted to sweep the top surface of said trays, a supply pipe extending into said tank, a thickened discharge outlet at the bottom of the tank, a thin pulp discharge near the top of said tank, and downwardl extending tubes forming passages throug said trays, said tube passageways being positioned adjacent the inner walls of the tank.

4. Settling apparatus including a, tank, a I

plurality of trays within said tank, a rotatable shaft extending upwardly through openings in said trays, horizontally extend ing arms on said shaft carrying rakes and extending immediately above said trays, a supply inlet near the bottom of the tank and an outlet for thickened pulp at the bottom of the tank separated from the inlet to prevent mingling of the pulp; downwardly extending short tubes secured to the under sides of said trays near their outer edges each communicating with an opening in its respective tray for the upward passage of pulp, said tubes being adapted to trap lighter fluids and gases, an outlet in -the wall of said tank close to the under side of said trays near said tubes, such outlets being connected directly with outlet tubes on the outside of said tank andextendingabove it for the escape of lighter fluids and gases; and downwardly extending tubes surrounding the shaft to supply a downward 5. Settling apparatus comprisin a settling tank having horizontally exten ing trays, a vertical rotatable shaft extending through passage from said trays for thickened pulp.

a central opening in each tray, horizontal arms supported on and operated by said shaft carrying rakes passing immediately above said trays, a supply intake in said tank, an outlet near the top of the tank for the fluid, said trays having openings near the wall of the tank for the upward passage of pulp and openings near the center -of the tray for the downward passage of pulp; downwardly extending short tubes about said openings for the upward passage of pulp adapted to trap ascending gases, the

tank being provided with openings through its wall cated immediately beneath the edges of the trays for the escape of said gases, pipes extending from said openings above the wall for decanting the gases from the tank, and downwardly extending tubes at the inner edge of each tray surrounding the shaft for conducting settled pulp downwardly from said trays to the outlet.

6. Settling apparatus comprising a plurality of superposed settling compartments having openings for the downward discharge of settled solids and separate open- 10 ings connecting adjacent compartments for the upward flow of supernatant liquid, and tubes extending from the edge of each of a i the latter openings downwardly a substantial distance into the subjacent compartment.

CLEMENT W. ANKENYQ 

